Happy Birthday Hubble!

During the 15 years that NASA’s Hubble Space
Telescope has orbited the Earth, it has taken three-quarters
of a million photos of the cosmos - images that
have awed, astounded and even confounded astronomers
and the public alike.

The Space Shuttle Discovery placed the Hubble Space
Telescope into Earth orbit on April 25, 1990, opening
a brand new era in astronomy. For the first time
ever, a large telescope that viewed in visible light
orbited above Earth's distorting atmosphere, which
blurs starlight making images appear fuzzy. After
installation of a new camera and a device that compensated
for an improperly grounded mirror, images of planets,
stars, galaxies, and nebula began pouring in –
all up to 10 times sharper than any previous telescope
had ever delivered.

Scientists using Hubble have compiled a long list
of scientific achievements since its launch 15 years
ago. Hubble has helped astronomers calculate the
precise age of the universe (13.7 billion years
old); helped confirm the existence of a strange
form of energy called dark energy; detected small
proto-galaxies that emitted their light when the
universe was less than a billion years old; proved
the existence of super-massive black holes; provided
sharp views of a comet hitting Jupiter; showed that
the process of forming planetary systems is common
throughout the galaxy; and has taken more than 700,000
snapshots of celestial objects such as galaxies,
dying stars, and giant gas clouds - the birthplace
of stars.

Some interesting Hubble Trivia:

In its 15 years of viewing the sky, NASA’s
Hubble Space Telescope has taken more
than 700,000 exposures and probed more
than 22,000 celestial objects.

The Hubble Ultra Deep Field (HUDF) is
the most observed area of the sky. Hubble
spent more than 500 hours viewing the
HUDF, snapping more than 1,100 photographs.

Hubble has whirled around Earth nearly
88,000 times, racking up 2.3 billion miles.
That is like making about 400,000 round
trips from New York City to Los Angeles.

The telescope’s observations have
produced 23 terabytes of data, equal to
the amount of text in 23 million novels.
The Hubble data would fill two Library
of Congress book collections.

Each day the orbiting observatory generates
enough data -- about 15 gigabytes -- to
fill more than three DVDs.

In Hubble’s 15-year lifetime, about
3,900 astronomers from all over the world
have used the telescope to probe the universe.

Astronomers have published more than
4,000 scientific papers on Hubble results.

All
about M51

by Rob Kennicutt (University of Arizona)

This
breathtaking image reveals the outbreak of newly
formed stars across the disk of the "whirlpool"
of M51, and the complex spiral network of dust and
gas clouds that are giving birth to these stars.
The complex web of dark filaments are actually dense
concentrations of gas seen in silhouette against
the bright disk of stars. These appear opaque because
of dust mixed with the gas, which blocks visible
light from penetrating inside. The red blobs and
bubbles that also appear interlaced with these dark
lanes are clouds of hot ionized gas which have been
lit up by massive young stars recently formed within
these clouds. Sometimes you can see the bright blue
stars or clusters embedded in these nebulae. And
nearly everywhere else in the spiral pattern you
can see thousands of other young stars and clusters
of bright blue stars; these are seen at later stages
after their birth, after they have blown away the
cocoons of gas and dust out of which they formed.

Most of what we see in this photograph--
the spectacular whirlpool of spiral structure, the
compressed filaments of gas and dust, the ionized
nebulae, and the profusion of young stars-- all
have been triggered by the collision of M51 with
its smaller companion galaxy, NGC 5195. Gravitational
forces from the passage of the two galaxies have
produced tides in the galaxies. These tides are
visible in NGC 5195 as smooth plumes of stars extending
beyond the main body of the galaxy. In M51 itself
the tides have combined with the rotation of the
galaxy to produce unusually strong spiral waves,
and these in turn have caused the interstellar gas
to compress and trigger the formation of new stars.

These
new images are being used for a variety of important
new scientific studies. The stars and star clusters
provide a fossil record of the history of the star
formation over hundreds of millions of years in
M51, and this in turn will help us to better understand
the processes that give birth to massive star clusters
and stars in general. The complex patterns of structure
in the dust filaments and gas clouds are providing
new insights into how the gas collects to form star-forming
clouds, and how efficiently these clouds manufacture
stars from their natal gas. And the unprecedented
detail of the images should teach us more about
how gas funnels into the central black hole of M51
and similar galaxies, to fuel violent outbursts
of nuclear activity.